Dehydrator having two live electrodes



c. EDDY DEHYDRATOR HAVING TWO LIVE ELECTRODES Dec. 29, 1 9 31.

% Eta Original Filed Dec. 28, 1926 ATTORNEY.

MW, w 1 m H Patented Dec. 29, 1931 UNITED STATES PATENT oFFIoE HAROLD G. EDDY, DE LOS ANGELES, CALIFORNIA, AS S IGNOR TO PETROLEUM BECTIFY- ING COIM'I'ANY OF CALIFORNIA,OF LOS ANGELES, CALIFORNIA, A CORPORATION OF CALIFORNIA DEEYDRATOR HAVING TWO LIVE ELECTRODES Application filed December 28, 1926, Serial No. 157,529. Renewed November 4, 1931.

This invention relates to the art of dehydrating emulsions and relates particularly to a dehydrator for dehydrating petroleum emulsions.

Petroleum as it is taken from the well often carries particles of water which must be separated from it before it is ofcommercialare coalesced into globules of suflicient size' to gravitate from the petroleum.

One of the difliculties encountered when treating emulsion of low resistance, that is, a very wet emulsion, is to maintain the proper otential difference between the electrodes to reak down the emulsion bonds without short-circuiting the apparatus and rendering it inoperative. The ordinary electric dehydrator has a tendency to short-circuit, not only to the sides of the treater, but to the bottom through the freed water particles which form a body at the lower part of the tank of the dehydrator.

It is an object of his invention to provide a dehydrator in which therewill be no shortcircuiting between the electrodes or between the electrodes and the tank.

The electrodes of a dehydrator are supported inside the tank by insulators. When an extremely high potential is impressed on the electrodes, say, 20,000 volts, the strain on the insulators is very great and they are liable to fail.

It is one of the objects of this invention to provide a dehydrator in which the strain on the insulators which support the electrodes is very greatly reduced. In the apparatus of my invention it is possible to impose .a potential of 20,000 volts on the electrodes but only a potential of 10,000 volts on the insulators.-

I accomplish the above objects of my .invention by providing a pair of live electrodes instead of using alive and grounded electrode as is common practice. The middle of the secondary of the transformer used to impress the voltage on the electrodes is ground-- ed and the tank is also grounded. By this construction a full potential is set up between the live electrodes but only one-half potential is set up between either of the electrodes and the tank.

It is another object of this invention to provide a dehydrator in which treated or par- Fig. 1 is a vertical section of a dehydrator embodying the features of the invention,

Fig. 2 is a section taken on the line 22 of fieferring in detail to the drawings my dc hydrator has a tank 11 which is provided.

with a water outlet 12 connected to the lower part thereof and-an-oil outlet 13 connected to'a dome 14 of a top 15.

Supported in the tank 11 near the central part thereof primary electrode 17 is supported by rods 18 which are connected to insulators 19, the insulators 19 being in turn supported by the top 15. One of the rods 18 extends throu h an inlet bushing 21 to the outside of t e.

tank 11 and hasa conductor 22 connected thereto, which conductor 22 is attached to a secondary 23 of a transformer 25. The primary electrode 17 has a mouth ortion 26 formed at'the upper end thereo which is conical. Connected to the mouth portion 26 at the lower end is a body portion 27 which is slightly conical, being smaller in diameter at its lower end.

Situated inside the primary electrode 17 is an auxiliary electrode 30. The auxiliary electrode 30 is supported by a rod 31 which extends upward through an insulator 32 supported by the top 15. The upper end of t is a primary electrode 17 The rod 31 is threaded as indicated at 33 and a the nut 34 resting on the upper end of the the auxiliary electrode 30 is in the form of a cone 38 and is located inside the mouth 26 of the primary electrode 17. Formed below the cone 38 is a body portion 39 which is slightly conical, being smaller at the lower end, and which is located inside the body portion 27 of the primary electrode 17. An annular space is provided between the pnmary and auxiliary electrodes, as indicated at 40, which annular space serves as a treating space.

Emulsion is supplied to the upper end of the treating space 40 by means of an annular inlet pipe 43 which is situated near the upper ends of the electrodes 17 and 30. The annular inlet pipe 43 has perforations 44 formed in the lower edge thereof from which the emulsion issues. Connected to the annular inlet pipe 43 is a pipe 46 which extends through the top 15 and through whlch emulsion is supplied to the annular pipe 43. S'urrounding the electrodes 17 and 30 in the tank 11 is a heater in the form of a C01]. 50 A heating medium such as steam may be clrculated through the coil 50 by pipes 52 wh1ch connect to the coil 50 and extendoutward through the tank 11. The coil 50 1s located adjacent to the middle parts of the electrodes.

The tank 11 is grounded by any suitable means such as a conductor 54. The secondary winding 23 is also grounded at a point between the ends thereof and preferably at the central point by any suitable means such as a conductor 55.

The operation of my invention issubstantially as follows:

hen the transformer is energized an electric field is set up in the treating space 40 between the primary and auxiliary electrodes 17 and by reason of the fact that the eleetrodes are connected to the electric circuit of the secondary. The voltage impressed on the treating space will be the maximum voltage of the secondary 23. Since the tank 11 is grounded and since the central part of the secondary 23 is grounded, a field between the primary electrode 17 and the tank 11 will be set up and also a field between the auxiliary electrode 30 and the tank will be set up. The strength of these fields will be in proportion to the part of the secondary 23 which is included in the individual circuits. Since the secondary is grounded. at the central part one-half of the secondary will be included in the circuit including the primary electrode and the tank, and one-half will be included in the circuit including the auxiliary electrode and the tank; therefore, the potential between the electrodes and the tank Will be equal to one-half the potential between the electrodes 17 and 30. If the potential impressed on the treating space 40 is 20,000 volts the voltage impressed between the electrodes and the tank 11 will be 10,000 volts.

The emulsion to be dehydrated is supplied to the upper end of the treating space 40 by the annular pipe 43. This (mulsion passes downward through the mouth 26 and between the body portions of the electrodes. The emulsion at this time is subjected to the action of the high potential gradient field and the water particles are coalesced into masses. As the emulsion leaves the lower end of the treating space 40 the oil passes around the lower end of the body 27 of the primary electrode 17 and upward as indicated by arrows 57. The masses of water which have been formed by the action of the electric field fall to the lower end of the tank 11, forming a body below the broken line 58. A heater in the form of the steam coil heats the oil and thus accelerates the upward flow of oil around the primary electrode 17. A portion of this oil which is very dry passes as indicated by arrows 59 to the dome l4 and is withdrawn from the dehydrator by means of the oil outlet pipe 13. Other warm oil passes as indicated by arrows 61, and is mixed with the emulsion passing from the annular pipe 43. The mixing of the clean oil with the emulsion reduces short-circuiting tendencies so that short-circuiting between the live electrodes 17 and 30 will be reduced to a minimum. By reason of the fact that the emulsion is cool whereas the treated oil is warm, the emulsion will fall rapidly through the treating space 40 and this tends to prevent short-circuiting. By reason of the fact that the potential between the electrodes 17 and 30 and the tank is quite low, short-circuiiing tendencies will be negligible. The constant circulation which takes place in the tank 1.1 absolutely prevents any short-circuiting whatsoever.

One very important feature of the invention is that the strain on the insulators 19, 21 and 32 is considerably lower than it would be on an ordinary dehydrator. By the arrangement shown the potential difference between the electrodes 17 and 30 is 20,000 volts but the potential difference between either of the electrodes and the tank is only 10,000 volts. In the ordinary dehydrator, if 20,000 volts were impressed on the electrodes the insulators would be subjected to a strain in proportion to the 20,000 volts, but in this invention the arrangement is such that the voltage im pressed on the electrodes may be 20,000 volts and the strain on the insulators is equal to that produced by only 10,000 volts. This is because of the fact that the potential difference between the electrodes and the tank is only 10,000 volts.

Another important feature of the invention is the adjustability of the auxiliary electrode 30. By rotating the nut 34, the rod 31 and the electrode 30 may be moved up or down. Since the body portion 27 of the primary electrode l7 and the body portion 39 of the auxiliary electrode 30 are. tapered, the relative movement between the electrodes changes the size of the treating space 40. 'When treating different oils different sizes of the treating space may be desired. Inasmuch as the cone 38 converges in one direction (i. e. upward) and the mouth portion 26 diverges in this direction, it follows that the voltage gradient on an'emulsion particle lying therebetween is lowered when the cone 38 is lowered. Thus, moving the cone 38 by means of the nut 34: changes the voltage gradientacross any horizontal section of the treating space between the-cone 38 and the mouth portion 26, a result often desirable. I

As thoroughly explained in the foregoing description a very important part of this invention is the provision of a dehydrator having two live electrodes, both of which are insulated from the tank. It is likewise a feature to ground the center of the secondary 23 and to ground the tank so that one-half the potential may be impressed between either of the electrodes and the tank.

I claim as my invention: I

1 In a dehydrator, the combination of: a tank; a primary live electrode in said tank;

' insulator means for supporting said primary live electrode; an auxiliary live electrode in said tank; insulator means for supporting said auxiliary live electrode, said electrodes being oppositely poled; means connected. to said primary and auxiliary live electrodes for impressing an electric field in a treating space provided between said primary and auxiliarylive electrodes; and means for delivering liquid to said treating space.

2. In a dehydrator, the combination of: a tank; a primary live electrode in said tank; insulator means for supporting said primary live electrode; an auxiliary live electrode in said tank; insulator means for supporting said auxiliary live electrode; means connected to said primary and auxiliary live electrodes for impressing an electric field in a treating space provided between said primary and auxiliary live electrodes; means for delivering liquid to said treating space; means for grounding said tank; and means for grounding said impressing means in such a manner as to cause an electric field of less magnitude than in said treating space to be established between .said tank and said primary and auxiliary live electrodes.

3. In a dehydrator, the combination of: a tank; a primary live electrode in said tank; insulator means for supporting said primary live electrode; an auxiliary live electrode in said tank; insulator means for supporting said auxiliary live electrode; a transformer having a secondary, said secondary being connected to said primary and auxiliary live electrodes for impressing an electric field in a treating space provided between said primary and auxiliary live electrodes; means for delivering liquid to said treatin space; and means for connecting said ta to an intermediate point of said secondary.

4:. In a dehydrator, the combination of: a primary electrode having walls diverging in a given direction; a secondary electrode disposed within said primary electrode and having walls converging in said given direction, said walls cooperating to form a treating space; means for establishing a diiference in potential between said electrodes; and means for moving one of said electrodes relative to the other to change the distance across said treating space.

5. In a dehydrator, the combination of: a primary electrode having walls diverging in a given direction; a secondary electrode disposed Within said primary electrode and having walls converging in said given direction to form a tapered treatingspace; means for introducing the emulsion to be treated into the larger end of said tapered treating space; and means for establishing a, difference in potentialbetween said electrodes.

6. In a dehydrator, the combination of: a tank; a primary and an auxiliary electrode in said tank; insulation means supporting said electrodes in said tank whereby said electrodes are insulated from said tank and from each other and means .for establishing a difference in potential between said electrodes and between said electrodes and said tank, the difference in potential between said primary and greater than the difference in potential between either of said electrodes and said tank.

7. In a dehydrator, the combination of:

a-primary electrode means providing a downward converging portion; an auxiliary electrode means axially aligned therewith and providing an upward converging portion, said electrode means cooperating in'defining an annular treating space; means foraxially moving one of said electrode means relative to the other of said electrode means whereby said auxiliary electrodes being the distance across said treating space is said electrodes and said tank; and fluid introduction means electrically connected to said tank for introducing fluid into the space between said primary and said auxiliary electrodes. I

9. A combination as defined in claim 6 including means for introducing an emulsion into the space between said electrodes, said emulsion being therein treated, and in which the lower portion of said tank provides a settling space wherein a conducting portion of said emulsion may settle out to form a conducting body of fluid the potential of which is the same. as the potential of said tank.

10. In a dehydrator, the combination of: a grounded tank; a primary electrode mounted in and insulated from said tank, said primary electrode being in the form of a sleeve open at its ends and being submerged in a liquid contained in said tank: an auxiliary electrode extending centrally in said primary electrode and cooperating therewith in providing an annular treating space, said auxiliary electrode being also insulated with respect to said tank; emulsion introducing means electrically connected to said tank and forcing an annular stream of emulsion longitudinally through said annular treating space; and potential supply means electrically connected to said tank and to both said primary and auxiliary electrodes for impressing across said primary and auxiliary electrodes a potential greater than the potential between said tank and either of said electrodes. I

i 11. In a dehydrator, the combination of: a pair of conical electrodes having common axes, the Walls of said electrodes diverging in opposite directions; and means for axially moving one of said electrodes relative to the other.

12. In combination: a central electrode of conical shape; a surrounding electrode around said central electrode to define a tapering treating space whereby a. longitudinal movement of said central electrode changes the distance between said electrodes at a given section of said field; means operatively connected to said central electrode for longitudinally moving this electrode relative to said surrounding electrode; means for setting up an electric fieldbetween said electrodes; and means for introducing emulsion into said electric field.

In testimony whereof, I have hereunto set my hand at Los Angeles, California, this 23rd day of December, 1926. i

HAROLD C. EDDY. 

